Loudspeaker with undulated membrane

Abstract

A loudspeaker provided with a frame (101), a membrane (103) and a drive unit (105). The membrane has an outer circumferential edge (104a) suspended from the frame and an inner circumferential edge (104b). The drive unit has a stationary part (106a) secured to the frame and a translatable part (106b) provided with a coil support (108b) secured to the inner circumferential edge of the membrane. The membrane includes a membrane body (104) which, viewed in a circumferential direction, has a pattern of folds radially extending between the inner circumferential edge and the flat outer circumferential edge of the membrane. The folds have a depth (d), which increases from the edges (104a, 104b) towards an area (104A) situated between both edges. In this area, the folds are provided with faces (204C), to which a spider (111) of the loudspeaker is secured. This loudspeaker combines a small height with a large stroke of the membrane.

Description

FIELD OF THE INVENTION[0001]The invention relates to a loudspeaker which is provided with a frame, a membrane and a drive unit.BACKGROUND OF THE INVENTION[0002]Such speakers are generally known. FIG. 8 of the accompanying drawing shows a known loudspeaker. This speaker has a frame (1), a membrane (2) and an electromagnetic drive unit (4). The membrane is formed by a conical body (2a) and has a flat outer circumferential edge (2b) and a flat inner circumferential edge (2c). The drive unit is provided with a stationary part (4a) and a movable part (4b). The stationary part, which includes a permanent magnet and a magnetic yoke, is secured to the frame. The movable part includes a voice coil and a cylindrical coil support (4b1). At its outer circumferential edge, the membrane is connected to the frame by means of a flexible suspension (6) and at its inner circumferential edge, it is adhered to the coil support, which in its turn is connected to the frame by means of a spider (8).[0003]...

AI Technical Summary

Benefits of technology

[0006]It is an object of the invention to provide a loudspeaker which can be given a small height without deteriorating its sound performance and with stable membrane movements during use.

[0008]The loudspeaker according to the invention is provided with a membrane body which is undulated in such a way that fold portions are provided in said area which are suitable for fixing the suspension means, such as a spider known per se. These integrated fold portions are situated at a considerable axial distance, i.e. the distance viewed along a movement direction of the membrane, to the suspended outer circumferential edge of the membrane. In this way, the loudspeaker according to the invention has a suspension which allows both a large stroke and stable movements of the undulated membrane. Moreover, the specific corrugation structure of the membrane allows excellent acoustical performance due to its excellent stiffness and light weight.

[0014]A shallow loudspeaker provided with a membrane as described above has an excellent sound performance, due to its good behavior at and above the first break-up. In other words, also at and above the first break-up there is hardly distortion of the reproduced sound.

[0020]It is to be noted that the loudspeaker according to the invention is suitable for sound reproduction in hifi, home, automotive, TV and multimedia systems and particularly suitable for applications having very small build-in depths.

Problems solved by technology

For this reason, there arise problems relating to the speaker's performance if a shallow speaker, i.e. a speaker having a small height, is required in certain applications.

Although the speaker known from JP-A 54-6523 comprises means for solving the problem relating to lack of stiffness of a faintly conical diaphragm, it causes another problem, viz. a problem relating to the instability of the diaphragm movements due to the small axial distance between the suspension means formed by the suspension ring and the spider.

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